It is known that some representatives of the 4H-pyrido[1,2-a]pyrimidine-4-ones exert significant antiallergic and ulcus preventing activity (EP-PS No. 217 673 and 218 423, BE-PS No. 873 192 and 873 194 and U.S. Pat. No. 4,122,274 and 4,457,932). Cyctoprotective activity of the 9-methyl-3-tetrazolyl-4-oxo-4H-pyrido[1,2-a]pyrimidine potassium salt was shown more in detail (Gastroenterology 1985 88, 1354).